The invention relates to a method for manufacturing pressed parts from hard metal, ceramic, sintered metal or likewise.
It is known to manufacture moulded parts from hard metal, ceramic, sintered metal or likewise with the help of pressing. The powder-like or granular material is to be prepared such that with an applied pressure force the pressed part gets a homogeneous structure and may be sintered. A usual shaping is the so-called direct pressing in correspondingly designed pressing moulds or matrices to which pressing stamps are allocated. Corresponding to the respective pressing pressure there results a differing density with the pressed part. Pressed parts with a lesser density however shrink on sintering greater than pressed parts with a higher density. By way of differently adjustable pressing distances for the upper and lower stamp it is attempted to minimize deviations of density. Nevertheless differing densities in practise may arise by way of differing pressing forces, which in turn with the same height of the pressed parts may, e.g. by way of filling fluctuations, be of a few percent. With the manufacture of pressed parts for e.g. hard metal cutting plates additionally also criteria of the immersing depth of the upper stamp up to the beginning of the edge clearance-angle in the matrix are to be adhered to in order to obtain a sharp cutting edge. Furthermore the complete height of the pressed part must be precisely adhered to.
In order to obtain as uniform a density as possible e.g. within a charge, it is known to measure the pressing force and subsequently to carry out a correction over the filling for the subsequent pressed part (DE 42 09 767 C1).